This invention relates to an air flow measuring apparatus for measuring the quantity of intake air to an internal combustion engine.
A conventional pulse-heating air flow measuring apparatus is designed to measure the air flow by heating a thermal resistor element intermittently and measuring the time until the resistor is cooled down by heat dissipation to a certain temperature, as described in Japanese Patent Unexamined Publication No. 61-185639 (filed on Feb. 12, 1985; laid-open on Aug. 19, 1986).
The air flow measuring apparatus of this type basis its operation on the detection of the resistor's temperature reaching a predetermined temperature, and therefore it necessitates a resistor for compensating the intake air temperature installed in the intake air path besides the thermal resistor element as a sensor for measuring the quantity of intake air.